When a guy finishes inside you can you really feel it?
It depends. If we cum at the same time, no. If I am clear minded enough to pay attention, yes.
Other then sensing the guy's body tense up and them relax, can you actually feel the warm rush of semen being injected into you? Since the vagina and semen are the same temperature I'm not sure how you could actually feel it
No, the pulsing is what I feel when I feel it.
Usually, yes.